Inflatable escape chute and method of manufacture



Oct. 7, 1969 a. B. HOLCOMBE 3,470,991

INFLATABLE ESCAPE CHUTE AND METHOD OF MANUFACTURE Filed March 20, 1968Ilia-4 INVENTOR.

GORDON B. HOLCOMBE ATTORNEYS United States Patent US. Cl. 193-25 ClaimsABSTRACT OF THE DISCLOSURE An inflatable double track escape chute andmethod of manufacture involving the steps of forming longitudinal,inflatable tubular members and cross inflatable tubular members whichare connected in fluid-tight communication -with a flexible sheetsecured across them to serve as a slide surface. The longitudinalmembers are preferably formed in sections connected in tandem with theaxes of the sections from top to bottom being progressively disposed atsmaller angles with respect to the horizontal, in order to provide asteep initial rapid escape slide which levels out to cushion and brakethe fall. An intermediate longitudinal tubular divider separating thetwo tracks is secured to the flexible sheet in collapsed condition afterthe tubular members are inflated and the flexible sheet is under acertain amount of tension. Then, when the divider tube is inflated itwill further tension the flexible sheet. The divider tube is preferablyof a straight axis to provide additional longitudinal tensioning to theflexible sheet.

This invention relates to an inflatable escape slide and moreparticularly, to an inflatable double slide having a central dividermember which provides a two track slide for greater evacuation capacity,and which gives additional tensioning and stiffening of the flexibleslide surface.

At the present time there is an increasing trend toward the developmentof jet passenger aircraft adapted for larger and larger passenger loads.Consequently, there is a growing concern over the ability of presentairport facilities to accommodate the rapid loading and unloading ofseveral hundred passengers from a single flight. It is obvious that, inthe event of an emergency landing or interruption of take-off wherein itis highly desirable that all personnel aboard leave the aircraft asrapidly as possible, the problems of mass disembarkation are magnifiedmanifold. In order to accommodate such increased demands, there haspreviously been developed a double inflatable slide which is describedin Holcombe US. Patent No. 3,370,684 dated Feb. 27, 1968. The doubleslide there shown comprises three longitudinal tubes of similarconfiguration, each having a series of sections formed in tandem whereintheir axes are at progressively smaller angles with respect to thehorizontal and with the junction between sections providing a bendableportion of the beam to cushion the fall of the evacuees. Such slideshave worked successfuly in that they provide greatly increasedaccommodation for evacuation but they suffer some disadvantage in thatthe flexible sheet slide surface is not sufficiently taut to provide aseffective a slide as might be desired.

It is, therefore, an object of this invention to provide an inflatableescape slide having vastly increased escape capacity.

It is a further object of this invention to provide an inflatable escapeslide with a central divided member to separate slide surfaces forincreased evacuation rate.

It is a further object of this invention to provide an inflatable doubleescape slide wherein the central divider tube has a single continuousaxis so that when inflated it tends to assume a straight configuration,and hence provides greater overall rigidity in conjunction with the se1- tioned longitudinal inflatable beams.

It is a further object of this invention to provide a method of forminga double escape slide wherein the divider tube is secured to the slidesurface after the longitudinal beams have been inflated to tension theslide surface sheet between them.

In carrying out this invention, I provide a pair of longitudinal beamswhich are sectioned in tandem at progressively smaller angles to thehorizon when inflated to form a relatively steep slide initially forrapid descent and gradually shallower slide to slow the evacuees at thebottom. The longitudinal beams are connected to two or more transversebeams, including one at the top and at the bottom, with a flexible slidesurface sheet bonded across them. Then, the tubular members are allinflated to tension the sheet between them. Thereafter, a longitudinaldivider tube is secured to the slide surface sheet while collapsed,preferably by bonding another sheet over the collapsed divider tube andto the slide surface sheet along both edges. Then, the divider tube isbrought into fluid communication with one of the longitudinal ortransverse inflatable members so that upon subsequent inflation thedivider tube will be inflated to further tension the slide surface.Preferably, the divider tube is of single straight axis so that wheninflated it will provide further longitudinal strength to the slidesurface.

Other objects and advantages of this invention will become apparent fromthe description following when read in conjunction with the accompanyingdrawings where:

FIG. 1 is a top slant view of an escape slide embodying features of myinvention;

FIG. 2 is a side elevation view of the escape slide;

FIG. 3 is a section view taken along line 3-3 prior to inflation of thecentral divider tube; and

FIG. 4 is a section view taken along line 33 of FIG. 1 after inflationof the central divider tube.

Referring now more particularly to FIGS. 1 and 2, my high-capacity,double escape slide 10 includes a pair of side beams 12, each of whichis formed in two or more sections, here shown as sections 12a, 12b, 12c,12d and 12e which are joined in tandem along junctions 14, with thetandem series of communicating sections being in continuouscommunication and being disposed at progressively smaller angles withrespect to the horizon when the escape slide is inflated and supportedbetween the aircraft A and the ground G. The progressively reducedangles provide for an initial rapid descent at the relatively steepupper sections 12a and 12b and, in addition, the hinge joints 14constitute yieldable members which further reduce the rate of descentwithout tending to spring back in a trampolene effect.

Interconnecting the upper ends of the side beams 12 and in inflatablecommunication therewith are upper and lower cross support members 16 and18 respectively. In addition, intermediate inflatable transverse members20 are provided to interconnect the beams at one or more locations alongthe length. These intermediate members may be of relatively smalldiameter since their primary function is not one of load bearing butmerely to maintain the separated parallel relationship of thelongitudinal beams 12 and 14 and to resist the rotational forces inthese beams when the slide surface is loaded.

Preferably, the beam sections are formed of diameters sufficient toresist maximum anticipated loads where needed, but small enough Wherepossible to minimize inflation volume. For that reason, the sections 12,however many are employed, progressively increase in diameter from theirtops where they merge with the cross member 16 to a maximum diameter atthe point of maximum beam loading which may occur at about theirmid-points. In the slide shown, this occurs at the second hinge joint 14where the rate angle of descent is reduced slightly. Through a range ofinclination angles, dependent upon the height of the upper anchor panel22 at the aircraft A, this joint is approximately midway between thebeam supports at A and G where bending moments are at a maximum. Atsubsequent hinge joints 14 the sections extend at progressively slighterangles further to increase the braking effects of friction. Finally thelowermost sections 12e taper down to the diameter of the bottom crossmember 18 which is preferably of a diameter which would enable a personof average height to sit on it with his feet at or near the groundconsidering a certain amount of com pression.

The top cross support member 20 is of extended length protruding beyondthe side beams 12 in order to form a substantial bearing member which,when inflated and secured by the anchor tab 22 bears firmly against thefuselage of the aircraft A so as to provide increased stability andinsure a straight escape route even in relatively high cross winds. Thediameter of the upper cross support member and diameters of the beamsconnecting their width are relatively small because beam bending momentsof the single beam are at a minimum near the beam supports at theaircraft and on the ground and it is desirable to reduce inflationvolume requirements when possible.

The actual sliding surface comprise a flexible sheet 24 which is bondedor otherwise secured to the longitudinal beams 12 to extend between themwith the beams providing lateral restraining means. However, because thelongitudinal beams are designed to yield somewhat under passenger load,there is a tendency for the slide surface to lose some tension inoperation, thereby excessively slowing the rate of descent. Therefore,for the purpose of dividing the slide surface into two separate slides,I provide a longitudinal central divider tube 26 which extendssubstantially the full length of the slide to provide additional tensionto the slide surface transversely and, because the divider tube 26 seeksa configuration having a straight axis, it maintains additionallongitudinal strength despite bending of the side support beams 14.

The slide is preferably manufactured by forming the longitudinal sidebeams 12 in the various sections 12a, 12b, etc. and joining them intandem as above described and in communication with the top and bottomsupport beams 16 and 18 and the intermediate cross members 20. Then,while the longitudinal beams 12 and cross members are still collapsed,the flexible slide surface 24 is bonded to the longitudinal side beamsand the top and bottom cross members 16 and 18. After the slide surfacesheet 24 is firmly bonded, the longitudinal members and the crossmembers are inflated whereby the slide surface sheet is placed underslight tension. While in this state, the central divider tube 26 isbonded to the slide surface while still in collapsed condition (FIG. 3)as by bonding a separate flexible sheet 28 over the divider tube andalong both sides to the slide surface. Then, the longitudinal beams maybe deflated and the divider tube 26 is brought into communication withone of the other inflatable members as by attaching a hose 30 betweenthe divider tube and one of the transverse members. Subsequently, whenthe slide tubes 12, 16, 18 and 20' are inflated, the divider tube 26will be inflated with them to the configuration shown in FIG. 4. Whenthe divider tube is so inflated, the slide sheet 24 is distorted out ofits normally planar configuration in order to accommodate thecylindrical configuration of the divider tube 26. Since the hold downsheet 28 is attached to the sheet 24 along lines which are pulled towardeach other by the inflated tube 26 the slide sheet 24 is not onlydivided by the tube 26 to form two slide chutes, but the sheet 24 istensioned further to form a more effective slide surface.

While this invention has been described in conjunction with preferredembodiments thereof, it is obvious that modifications and changestherein may be made by those skilled in the art without departing fromthe spirit and scope of this invention as defined by the claims appendedhereto.

What is claimed as invention is: 1. The method of manufacturing aninflatable escape slide comprising the steps of:

forming a pair of first flexible tubular members, forming at least twosecond flexible tubular members, securing said tubular members togetherin fluid-tight communication with the first members displacedlongitudinally and spaced to form side rails when inflated and thesecond members forming transverse supported members, securing a flexiblesheet across said longitudinal tubular members, introducing a pressurefluid to inflate said tubular members, while said tubular members areinflated securing a collapsed, hollow, flexible divider tube to saidflexible sheet intermediate said longitudinal tubular members, andthereafter connecting said divider tube to one of said tubular membersfor fluid communication therewith. 2. The method defined by claim 1wherein: said divider tube is secured to said flexible sheet bydisposing a second flexible sheet over said divider tube While collapsedand securing it along opposite sides to said flexible sheet. 3. Themethod defined by claim 1 wherein: each of said first pair of tubularmembers is formed in at least two sections joined in tandem with theaxes thereof when inflated being disposed at a progressively smallerangle from top to bottom with respect to a horizontal plane, and saiddivider tube is formed with a straight axis, said divider tube beingsecured to said flexible sheet to extend at least across the junctionbetween said two sections, 4. An inflatable escape slide comprising: apair of generally parallel side support tubular beams, at least twotubular cross support members communicating with said side supportbeams, a flexible sheet secured across said side support beams,

and an intermediate divider tube generally parallel to said side supportbeams and secured to said flexible sheet, said divider tube beingsecured over a suflicient extent of its periphery in cross-section todistort and apply tension to said flexible sheet when said divider tubeis inflated. 5. The inflatable escape slide defined by claim 4 wherein:

said tubular beams are formed in at least two sections joined in tandemwith the axes of lower sections being disposed when inflated atprogressively reduced angles with respect to the horizontal, and saiddivider tube is formed with a straight axis and is of sufiicient lengthto extend between at least two pairs of sections of said side supportbeams, said divider tube being in fluid communication with at least oneof said support members.

References Cited UNITED STATES PATENTS 3,070,203 12/1962 Hailstone 193253,092,232 6/1963 Adams 193-25 3,370,684 2/1968 Halcombe 193-25 3,433,3423/1969 SWitlik l93-25 ANDRES H. NIELSEN, Primary Examiner US. Cl. X.R.244-l37

